TWI497559B - Ultraviolet discharge lamp - Google Patents

Description

Ultraviolet discharge lamp

The present invention relates to an ultraviolet discharge lamp used in, for example, a liquid crystal panel manufacturing step in which a polymer material subjected to ultraviolet radiation is polymerized or cured.

This application is based on Japanese applications filed on July 23, 2009, patents 2009-171809, Japanese applications filed on July 23, 2009, patents 2009-171810, and Japanese applications and patents filed on May 18, 2010. The benefit of the priority of 2010-114013. Claim the benefits of priority based on this. The contents of all of the aforementioned Japanese applications are incorporated herein by reference.

In the prior ultraviolet fluorescent lamp, a discharge medium containing mercury and a rare gas was sealed inside an arc tube made of soda lime glass, and a pair of electrodes were disposed in such a manner that no low-pressure mercury vapor discharge occurred inside the arc tube. Further, at least one of Ce (MeBa)Al ₁₁ O ₁₉ , YPO ₄ :Ce, LaPO ₄ :Ce or the like having a near-ultraviolet light having an emission wavelength of 320 to 400 nm or a combination thereof is applied to the light-emitting tube. On the other hand, it is possible to simultaneously obtain light of a UV-A region having high internal permeability of the ultraviolet curable resin and a strong UV-C light for hardening the surface of the ultraviolet curable resin on one lamp. (Japanese Laid-Open Patent Publication No. 2002-358926. hereinafter referred to as "Patent Document 1".)

According to the technique of the above Patent Document 1, the mercury enters the arc tube due to the change of the mercury over time, so that the transmittance of the bulb is lowered to cause a difference in the illuminance distribution in the longitudinal direction, or the conversion efficiency is lowered due to the mercury adsorption of the phosphor in the lighting. There is a problem that it is impossible to maintain a specific UV intensity.

SUMMARY OF THE INVENTION An object of the present invention is to provide an ultraviolet discharge lamp which can reduce the illuminance difference in the axial direction of a lamp and improve the maintenance ratio of the illuminance of the lamp.

In order to solve the above problems, an ultraviolet discharge lamp of the present invention includes an arc tube formed of soda lime glass, an inert gas for starting to be enclosed in the body of the arc tube, mercury, and an inner side of the arc tube. One pair of discharge electrodes is set, and the amount of phosphor having a peak of conversion efficiency of 253.7 nm and having a peak of conversion efficiency between 300 and 340 nm is set to N (mg), and the inner surface area to be coated is set to S. In the case of (cm ² ), the phosphor is coated on the inner wall of the arc tube under the condition that N/S is 2 < (N/S) < 7.

Hereinafter, embodiments for carrying out the invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a view showing a first embodiment of the ultraviolet discharge lamp of the present invention, and an example of the ultraviolet discharge lamp in Fig. 1 is a part of a configuration diagram of a hot cathode low-pressure mercury lamp.

In Fig. 1, reference numeral 11 denotes a transparent light-emitting tube made of a cheap soda lime glass having a transmittance of 80% or more and a Na ₂ O (sodium oxide) of 10% or more at a wavelength of 340 nm. The transmittance of the arc tube in the case of using soda lime glass is as shown in Fig. 2, and a transmittance of 80% or more can be obtained at a wavelength of 340 nm.

The arc tube 11 has, for example, a tube diameter D of 38 mm, a tube length L of 2367 mm, and electrodes 121 and 122 at both ends. In the electrode 121, both ends of the coil-shaped tungsten filament lamp 14 are supported by the conductive lead 131. The lead wire 131 penetrates the glass press seal portion 15. The electrode 122 is also configured in the same manner as the electrode 121. Lead on the side of the electrode 121 The lead wires on the side of 131 and the electrode 122 are connected to the pin-shaped contacts 171 and 172 on the respective bases 161 and 162 fixed to the opposite ends of the lamp.

Further, the arc tube 11 is sealed with a rare gas such as argon (Ar) gas and a certain amount of mercury at a low pressure of about 1 to 10 Torr.

Fig. 3 shows the luminance of wavelengths of NP-806, NP-805, and NP-807 manufactured by Nichia Chemical Co., Ltd., among various phosphors coated on the inner surface of the arc tube 11. Here, NP-806 is suitable as the phosphor 18 having a peak of conversion efficiency between wavelengths of 300 to 340 nm. The NP-806 is composed of LaPO ₄ (yttrium phosphate): Ce (铈).

When electric power is supplied from the electrodes 121 and 122 of the hot cathode low-pressure mercury lamp thus constructed, as shown in FIG. 4, the characteristic of the spectral distribution having a peak at a wavelength of 300 to 340 nm can be secured.

Fig. 5 shows the relative ultraviolet illuminance (%) per fluorometer (mg/cm ² ) for NP-806 for the phosphor 18 system. That is, the amount of the phosphor of the phosphor 18 is the highest in the case where the amount of the phosphor on the inner surface of the arc tube 11 is applied in a unit internal surface area of 3.9 mg/cm ² . When the relative ultraviolet ray illuminance becomes high, the treatment efficiency (time or reactivity) becomes high, which is effective.

As a result, by optimizing and specifying the optimum conditions of the conversion efficiency of the phosphor 18 and the transmittance of the ultraviolet light, the distribution in the axial direction can be improved.

Here, when the amount of phosphor having a mercury spectrum of 253.7 nm and having a peak of conversion efficiency between 300 and 340 nm is N (mg), and the inner surface area of the coating is S (cm ² ), The phosphor 18 is applied to the inner wall of the arc tube 11 under the condition that the predetermined value is 2 < (N/S) < 7.

When the value of N/S is less than 2, the transmittance increases, but since the amount of the phosphor is small, the luminous efficiency decreases, and the adsorption of mercury on the arc tube increases, and the ultraviolet retention rate decreases. Conversely, if the value of N/S is more than 7, the converted ultraviolet light is absorbed by the phosphor, so the amount of ultraviolet light emitted from the outside of the lamp is reduced. When NP-806 is used as the phosphor 18, the optimum value of the coating amount is about 3.9 mg/cm ² .

Although the thinner the coating amount of the phosphor 18, the smaller the left-right difference, the lower the conversion efficiency or the deterioration of the bulb to the phosphor. On the other hand, in the embodiment of the present embodiment, coating by the amount of phosphors satisfying the relationship of 2 < (N/S) < 7 can suppress deterioration of the phosphor 18 and reduce illuminance difference in the axial direction. Here, if the value of N/S is under the condition of 2.4 < (N/S) < 5.7, the relative ultraviolet ray illuminance is 95%, which is preferable.

6 and 7 are views for explaining a second embodiment of the ultraviolet discharge lamp of the present invention. Fig. 6 is a cross-sectional view showing only an important portion cut away and enlarged, and Fig. 7 is an explanatory view for explaining the effect of Fig. 6.

According to the present embodiment, as shown in FIG. 6, a protective film 61 formed by coating aluminum oxide (Al ₂ O ₃ ), for example, by coating, is interposed between the arc tube 11 and the phosphor 18, and is laminated on the cross section. The state of the arc tube 11, the phosphor 18, and the protective film 61.

The protective film 61 can suppress mercury from entering the arc tube 11, and can suppress a decrease in transmittance of the arc tube 11. Therefore, the maintenance rate of the illuminance can be suppressed from decreasing as the aging changes.

According to the present embodiment, application of the amount of phosphor that satisfies the relationship of 2 < (N/S) < 7 suppresses deterioration of the phosphor 18 and reduces illuminance difference in the axial direction, and the illuminance maintenance ratio can be improved.

Further, by the action of the protective film 61, mercury can be prevented from entering the arc tube 11, and the illuminance maintenance rate can be improved. As shown in Fig. 7, this point was confirmed to be one of the protective films, and the illuminance of 90% was maintained even after 1200 hours.

According to the present embodiment, it is possible to improve the illuminance maintenance rate by reducing the illuminance difference in the axial direction and providing a protective film.

8 and 9 are views for explaining a third embodiment of the present invention. Fig. 8 is an explanatory view for explaining the illuminance distribution per unit area, and Fig. 9 is an explanatory view for explaining the illuminance distribution per unit area of the embodiment.

In the present embodiment, the phosphor 18 of the ultraviolet discharge lamp described with reference to Fig. 1 is a phosphor 181 in which yttrium (La) is added at a phosphor weight ratio of 0.5%. The addition of the phosphor 181 having a ruthenium suppresses the adsorption of mercury, thereby suppressing the deterioration of the phosphor 181.

Further, the addition amount of ruthenium does not include 0% and is preferably 2% or less, and more than 2% causes a decrease in conversion efficiency or transmittance, which causes a decrease in ultraviolet light output.

That is, the illuminance per unit area of the lamp axis direction of the previous phosphor to which no ruthenium was added was as shown in FIG. Further, the illuminance per unit area of the lamp axis direction of the phosphor of the present invention to which the ruthenium is added has a distribution as shown in Fig. 9 .

When the enthalpy was not added, as shown in Fig. 8, it was found that the illuminance decreased from 48 hours to 100 hours. Further, when a flaw is added, as shown in Fig. 9, even if the lighting time elapses for 100 hours, the same illuminance as that of the lighting time of 24 hours can be obtained.

Here, the relationship between the amount of enthalpy added and the reliability of illuminance will be described with reference to FIG.

That is, when the initial illuminance of the untwisted enthalpy was set to 100%, the luminescence spectrum was observed, and the illuminance maintenance ratio after 2,000 hours passed was 85.7%. The initial illuminance was 99% when 0.5% of ruthenium was added, and the luminescence spectrum was the same as that in the case where ruthenium was not added, and the illuminance maintenance rate after 2,000 hours was 91.8%. Similarly, the illuminance maintenance rate after 2000 hours after the addition of 2.0% was 90.8%.

In addition, the initial illuminance when the addition of 3.0% was 78%, the luminescence spectrum was the same as that in the case where ruthenium was added, but the illuminance retention rate after 2,000 hours was 88.2%.

Therefore, it can be seen that the illuminance retention rate after 2,000 hours is 90% or more, and if it is too large, it is difficult to maintain the illuminance, and it is possible to achieve an amount not including 0% to 2.0% or less.

According to the present embodiment, by adding yttrium to the phosphor in a range in which the weight ratio of the phosphor does not include 0% and 2% or less, sufficient illuminance can be obtained over a long period of time.

Fig. 11 and Fig. 12 are views for explaining a fourth embodiment of the ultraviolet discharge lamp of the present invention. Fig. 11 is a cross-sectional view showing only an important portion cut away and enlarged, and Fig. 12 is an explanatory view for explaining the effect of Fig. 11.

In the present embodiment, in addition to the above-described third embodiment in which ruthenium is added to the phosphor, as shown in Fig. 11, for example, alumina (Al ₂ O ₃ ) is coated between the arc tube 11 and the phosphor 181. The protective film 61 formed in a manner is configured such that the light-emitting tube 11, the phosphor 181, and the protective film 61 are laminated on the cross section.

The protective film 61 can suppress mercury from entering the arc tube 11, and suppress a decrease in transmittance of the arc tube 11. Therefore, the maintenance rate of the illuminance can be suppressed from decreasing as the aging changes.

Fig. 12 is a graph showing that the illuminance varies with the change over time in the longitudinal direction of the lamp, and the illuminance per unit area which is the same as the elapsed time after elapse of 100 hours does not change, indicating that the illuminance maintenance ratio by the protective film 61 is improved. .

According to the present embodiment, the deterioration of the phosphor can be suppressed by the addition of ruthenium, and the illuminance difference in the axial direction can be reduced. Further, by the action of the protective film, mercury can be prevented from entering the arc tube, and the illuminance maintenance rate can be improved.

Furthermore, the present invention is not limited to the above embodiment. For example, it can be produced by using a general ultraviolet light-emitting cathode lamp. Therefore, it can be applied to a lamp of more than 2,500 mm required to irradiate the same lamp with a light-emitting length of a large-sized panel such as a next-generation liquid crystal substrate.

Further, the light-emitting tube is exemplified by soda-lime glass, but hard glass or semi-hard glass may be used as long as it has a transmittance of 80% at a wavelength of about 340 nm. In the case of soda lime glass and hard glass, since the short-wavelength transmittance of the hard glass is good, high illuminance can be obtained.

According to the embodiment of the present invention described above, the illuminance in the axial direction of the lamp can be reduced by specifying the amount of the phosphor, and the maintenance ratio of the illuminance of the lamp can be improved.

11‧‧‧Light tube

14‧‧‧Tungsten lamp

15‧‧‧ Sealing Department

18, 181‧‧‧ fluorescent body

61‧‧‧Protective film

121, 122‧‧‧ electrodes

131‧‧‧ lead

161, 162‧‧‧ pedestal

171, 172‧‧ ‧ pin contacts

Fig. 1 is a view showing a configuration in which a part of the first embodiment of the ultraviolet discharge lamp of the present invention is cut away.

Figure 2 is a diagram for explaining the ultraviolet transmittance of a general soda lime glass. Figure.

Fig. 3 is an explanatory view for explaining wavelengths emitted by the phosphor used in the present invention.

Fig. 4 is an explanatory view for explaining the light emission distribution of the phosphor used in the present invention.

Fig. 5 is an explanatory view for explaining the relationship between the amount of phosphor and the illuminance of ultraviolet rays.

Fig. 6 is a cross-sectional view showing only a portion of the second embodiment for explaining the ultraviolet discharge lamp of the present invention, which is cut away and enlarged.

Fig. 7 is an explanatory view for explaining the effects of the second embodiment of the present invention.

Fig. 8 is an explanatory view for explaining an illuminance distribution with respect to a time lapse of a previous lamp longitudinal direction in which no enthalpy is added in the third embodiment of the present invention.

Fig. 9 is an explanatory view for explaining an illuminance distribution of a time passage in the longitudinal direction of the lamp of the present invention with respect to the addition of the crucible according to the third embodiment of the present invention.

Fig. 10 is an explanatory diagram for explaining the relationship between the amount of addition of enamel and the reliability of illuminance.

Fig. 11 is a cross-sectional view showing only a portion of the fourth embodiment for explaining the ultraviolet discharge lamp of the present invention, which is cut away and enlarged.

Fig. 12 is an explanatory view for explaining the effects of the fourth embodiment of the present invention.

11‧‧‧Light tube

14‧‧‧Tungsten lamp

15‧‧‧ Sealing Department

18‧‧‧Fertior

121, 122‧‧‧ electrodes 121, 122

131‧‧‧ lead

161, 162‧‧‧ pedestal

171, 172‧‧ ‧ pin contacts

Claims (2)

An ultraviolet discharge lamp comprising: a glass-made light-emitting tube containing 10% or more of sodium oxide in 100% of a mother material and having a transmittance of 80% at a wavelength of about 340 nm; sealed in the aforementioned light-emitting tube An inert gas and mercury are used for starting in the body; and a pair of discharge electrodes are disposed opposite to the inside of the arc tube; coated on the inner wall of the arc tube to convert a mercury spectrum of 253.7 nm and have a peak of conversion efficiency between 300 and 340 nm a phosphor; and a protective film formed of the aluminum oxide (Al ₂ O ₃ ) formed between the phosphor and the arc tube; and the amount of the phosphor is N (mg), and the coating is as described above When the inner surface area of the inner wall of the arc tube is S (cm ² ), the condition that N/S is 2.4 < (N/S) < 5.7 is satisfied. The ultraviolet discharge lamp of claim 1, wherein the phosphor is added with a lanthanum (La) powder in a weight ratio of 2% or less and more than 0% based on the weight of the phosphor.